Lecture to 1st year students, Kulliyah
of Medicine, International Islamic University, Kuantan on 14th
November 1997 by Prof Dr Omar
Hasan Kasule, Sr. Deputy Dean for Research and Post-graduate Affairs

OUTLINE

INTRODUCTION

HISTORY OF CANCER EPIDEMIOLOGY

DESCRIPTIVE EPIDEMIOLOGY OF CANCER

PURPOSES OF DESCRIPTIVE EPIDEMIOLOGY

MEASUREMENT OF CANCER

TRENDS OF CANCER

TYPES OF CANCER DATA

SOURCES OF DATA ON CANCER

METHODS OF CANCER EPIDEMIOLOGY

ENVIRONMENTAL RISK FACTORS

INTRODUCTION

Cancer Epidemiology deals with the distribution, determinants (causes) and prevention of
cancer. It also extends to deal with aspects of cancer treatment. Epidemiology being a quantitative medical science deals
with numbers and figures.

Cancer is not one disease. It is many diseases each with its risk factors and different
methods of treatment and prevention.

Cancer is a global problem affecting all countries of the world and all humans irrespective
of ethnicity, age, and socio-economic status

HISTORY OF CANCER EPIDEMIOLOGY

1713:Ramazzini recorded high cancer in nuns (nulliparous)

18th centuryHill
observed cancer of the nose in snuff users

18th centurySoemmering
observed cancer of the lower lip in pipe

smokers

?Percival Pott recorded high cancer of the scrotum in

chimney sweeps

1895:Bladder cancer associated with work in the dye stuff

industry

1956Smoking and lung cancer among British doctors

DESCRIPTIVE EPIDEMIOLOGY OF CANCER

Geographical variation

Ethnic/racial variation

Socio-economic variation

Socio-cultural variation

Age distribution

Sex distribution

Time trends

Migratory patterns

Site distribution

PURPOSES OF DESCRIPTIVE EPIDEMIOLOGY

Understand the public health impact of cancer

Study how cancer burden varies from place to place

Understand temporal changes and trends

Get clues about causation and avoidability

MEASUREMENT OF CANCER

Incidence

Prevalence (cancer burden)

Mortality

Survival

TRENDS OF CANCER

There are approximately 8 million new cases of cancer a year. With the decrease of infectious
diseases, increasing life-spans in all countries of the world in addition to increasing exposure to environmental and industrial
cancer risk factors, incidence and mortality due to cancer are increasing as a proportion of total morbidity and mortality.

TYPES OF CANCER DATA

Epidemiological

Laboratory (biological, pathological, chemical, molecular)

Clinical

Environmental

SOURCES OF DATA ON CANCER

National or Regional Cancer Registries

Death Certificate Data

Hospital Records

Special Surveys and Studies

METHODS OF CANCER EPIDEMIOLOGY

DESCRIPTIVE

Incidence

Prevalence

ANALYTIC

Causal association

Prospective and retrospective

Correlation

Migratory studies

INTERVENTION

Primary prevention

Diet

Environment

Education

Control infections

Secondary prevention

Tertiary prevention

PREVENTION

Epidemiological data used to prevent cancer even without knowing the exact cause(s)

Epidemiology helps cancer prevention by manipulation of exposure to environmental exposures
and life-style

Education

Intervention

Screening for early detection

Prevention strategies for given cancers

Lungstop smoking, new cigarettes, diet

Mouthstop quid smoking, stop tobacco chewing

LiverHBV immunisation, aflatoxin

Cervixgenital hygiene, sexual behaviour

ENVIRONMENTAL RISK FACTORS

Time of exposure

Duration of exposure

Age at exposure

Identified risk factors

Tobacco

Occupation

Radiation

Alcohol

Diet

Drugs

Reproductive Factors

Air Pollution

Microbial agents

TREATMENT OF CANCER

Strategies

Curative eg BL, leukemia

Supportive

Treatment modalities

Surgery

Chemotherapy

Irradiation

Immunotherapy

LIFE-TIME CANCER RISK: PROBABILITY OF DEVELOPING
CANCER WITHIN SPECIFIED PERIODS OF TIME BY PERSONS AT SELECTED AGES PREVIOUSLY UNDIAGNOSED WITH CANCER OF THAT SITE BY RACE
AND SEX US 1970

CANCER AROUND THE WORLD, 1988-1991, DEATH RATES
PER 100,000 POPULATION FOR 46 COUNTRIES

BASIC TERMINOLOGY OF CANCER BIOLOGY

Hyperplasia is increase in the number of cells

Dysplasia is a reversible regressive change in cells marked by variation in size, shape, and orientation

Anaplasia is irreversible change toward lesser differentiation

Tumor or neoplasm is an autonomous new tissue

Benign tumor is non-invading. Non-metastasising and slow-growing

Malignant Tumor is the opposite of benign

Cancer is a malignant neoplasm

Grade refers to the degree of histological differentiation of a tunor

Primary tunor is one that is contigous with the site of origin

Metastatic or secondary tumor is one that originates from a previously existing, anatomically
separate tumor

Stage is the degree to which a tumor extends beyond its site of origin. In-situ is entirely confined to the tissue of origin.
Localised is confined to the organ of origin. Regional is confined to tissue adjacent to the organ of origin including regional
lymph nodes. Distant extends beyond the bounds of the regional

Carcinoma is a malignant neoplasm of epithelial cells, It can be epidermoid or squamous cell carcinoma, transitional cell carcinoma,
or an adenocarcinoma. Most of cancers are epithelial

Sarcoma is a malignant neoplasm of connective tissue

Lymphoma. Myeloma, and leukemias are malignant neoplasms of hematopoietic cells

Initiation is an irreversible alteration in a tissue induced by exposure to a carcinonogen.
Irradiation is an example of an initiator

Promotion is a process in which a initiated tissue is selectively stimulated to develop focal proliferation. Saccharin is an
example of a promoter

Progression is the process by which initiated/promoted cells turn into cancer. Estrogens are an example of a progression agent

Induction period

latent period

INTRODUCTION

Cancer Epidemiology deals with the distribution, determinants (causes) and prevention of
cancer. It also extends to deal with aspects of cancer treatment. Epidemiology being a quantitative medical science deals
with numbers and figures.

Cancer is not one disease. It is many diseases each with its risk factors and different
methods of treatment and prevention.

Cancer is a global problem affecting all countries of the world and all humans irrespective
of ethnicity, age, and socio-economic status

HISTORY OF CANCER EPIDEMIOLOGY

1713:Ramazzini recorded high cancer in nuns (nulliparous)

18th centuryHill
observed cancer of the nose in snuff users

18th centurySoemmering
observed cancer of the lower lip in pipe

-smokers

?Percival Pott recorded high cancer of the scrotum in

chimney sweeps

1895:Bladder cancer associated with work in the dye stuff

industry

1956Smoking and lung cancer among British doctors

DESCRIPTIVE EPIDEMIOLOGY OF CANCER

Geographical variation

Ethnic/racial variation

Socio-economic variation

Socio-cultural variation

Age distribution

Sex distribution

Time trends

Migratory patterns

Site distribution

PURPOSES OF DESCRIPTIVE EPIDEMIOLOGY

Understand the public health impact of cancer

Study how cancer burden varies from place to place

Understand temporal changes and trends

Get clues about causation and avoidability

MEASUREMENT OF CANCER

Incidence

Prevalence (cancer burden)

Mortality

Survival

TRENDS OF CANCER

There are approximately 8 million new cases of cancer a year

With the decrease of infectious diseases, increasing life-spans in all countries of the
world in addition to increasing exposure to environmental and industrial cancer risk factors, incidence and mortality due
to cancer are increasing as a proportion of total morbidity and mortality.

TYPES OF CANCER DATA

Epidemiological

Laboratory (biological, pathological, chemical, molecular)

Clinical

Environmental

SOURCES OF DATA ON CANCER

National or Regional Cancer Registries

Death Certificate Data

Hospital Records

Special Surveys and Studies

METHODS OF CANCER EPIDEMIOLOGY

DESCRIPTIVE

Incidence

Prevalence

ANALYTIC

Causal association

Prospective and retrospective

Correlation

Migratory studies

INTERVENTION

Primary prevention

Diet

Environment

Education

Control infections

Secondary prevention

Tertiary prevention

PREVENTION

Epidemiological data used to prevent cancer even without knowing the exact cause(s)

Epidemiology helps cancer prevention by manipulation of exposure to environmental exposures
and life-style

Education

Intervention

Screening for early detection

Prevention strategies for given cancers

Lungstop smoking, new cigarettes, diet

Mouthstop quid smoking, stop tobacco chewing

LiverHBV immunisation, aflatoxin

Cervixgenital hygiene, sexual behaviour

ENVIRONMENTAL RISK FACTORS

Time of exposure

Duration of exposure

Age at exposure

Identified risk factors

Tobacco

Occupation

Radiation

Alcohol

Diet

Drugs

Reproductive Factors

Air Pollution

Microbial agents

TREATMENT OF CANCER

Strategies

Curative eg BL, leukemia

Supportive

Treatment modalities

Surgery

Chemotherapy

Irradiation

Immunotherapy

LIFE-TIME CANCER RISK: PROBABILITY OF DEVELOPING
CANCER WITHIN SPECIFIED PERIODS OF TIME BY PERSONS AT SELECTED AGES PREVIOUSLY UNDIAGNOSED WITH CANCER OF THAT SITE BY RACE
AND SEX US 1970

CANCER AROUND THE WORLD, 1988-1991, DEATH RATES
PER 100,000 POPULATION FOR 46 COUNTRIES

BASIC TERMINOLOGY OF CANCER BIOLOGY

Hyperplasia is increase in the number of cells

Dysplasia is a reversible regressive change in cells marked by variation in size, shape, and orientation

Anaplasia is irreversible change toward lesser differentiation

Tumor or neoplasm is an autonomous new tissue

Benign tumor is non-invading. Non-metastasising and slow-growing

Malignant Tumor is the opposite of benign

Cancer is a malignant neoplasm

Grade refers to the degree of histological differentiation of a tunor

Primary tunor is one that is contigous with the site of origin

Metastatic or secondary tumor is one that originates from a previously existing, anatomically
separate tumor

Stage is the degree to which a tumor extends beyond its site of origin. In-situ is entirely confined to the tissue of origin.
Localised is confined to the organ of origin. Regional is confined to tissue adjacent to the organ of origin including regional
lymph nodes. Distant extends beyond the bounds of the regional

Carcinoma is a malignant neoplasm of epithelial cells, It can be epidermoid or squamous cell carcinoma, transitional cell carcinoma,
or an adenocarcinoma. Most of cancers are epithelial

Sarcoma is a malignant neoplasm of connective tissue

Lymphoma. Myeloma, and leukemias are malignant neoplasms of hematopoietic cells

Initiation is an irreversible alteration in a tissue induced by exposure to a carcinonogen.
Irradiation is an example of an initiator

Promotion is a process in which a initiated tissue is selectively stimulated to develop focal proliferation. Saccharin is an
example of a promoter

Progression is the process by which initiated/promoted cells turn into cancer. Estrogens are an example of a progression agent